Peptidomics profiling identifies endogenous peptides associated with meningeal afferent activation in a chronic...

Migraine is a highly disabling disorder with a high prevalence, significantly impairing quality of life. Emerging evidence suggests that circulating endogenous peptides play critical roles in neurovascular regulation and nociceptive signaling. However, the contribution of blood-derived endogenous peptides to the activation of meningeal afferents and the pathophysiology of migraine remains poorly understood. Therefore, investigating the role of these peptides in the meninges is crucial for elucidating the mechanisms underlying migraine. To elucidate the role of endogenous peptides in activating meningeal afferents during migraine, we established a chronic migraine mouse model using nitroglycerin (NTG). Serum peptidomic analysis was performed to identify differentially expressed peptides between the Negative Group (NEG) and NTG group. Functional enrichment analysis revealed significant upregulation of pathways associated with prolactin signaling and hypoxia-inducible factor-1 (HIF-1) signaling. Subsequently, peptidomic profiling of the meninges was conducted in both groups. Integration of meningeal and serum peptidomic datasets, together with a curated set of endogenous secreted proteins, enabled cross-comparative analysis to identify circulating peptides with potential effects on the meninges. This analysis revealed a marked increase in both pituitary adenylate cyclase-activating polypeptide (PACAP) and calcitonin gene-related peptide (CGRP), two key mediators critically implicated in migraine pathophysiology.In addition, several PACAP-related short peptide fragments were identified, some of which exhibited sequence homology to known bioactive domains. Collectively, these findings suggest that PACAP and CGRP, along with their derived peptide fragments, may contribute to the activation of meningeal nociceptive fibers and thereby participate in the initiation and maintenance of migraine. Peptidomics sequencing of the TNC region was performed, and functional enrichment analysis of the differentially expressed proteins indicated the dysregulation of diverse biological pathways. These findings reveal that CGRP and PACAP may play a key role in the activation of meningeal afferents in a chronic migraine mouse model. Several protein modification sites are thought to be crucial mechanisms in endogenous peptides-mediated meningeal activation.